Generally, a refrigerator comprises a freezing chamber and a cooling chamber. A storage chamber is separately provided at a specific location in the cooling chamber so as to store vegetables and fruits (hereinafter, which will be commonly called “vegetables”) or meats and fishes in a more fresh state by optimizing humidity. Therefore, the storage chamber in the cooling chamber may be an example of a foodstuffs storage container.
A conventional refrigerator having a foodstuffs storage container will now be described with reference to FIG. 1.
The conventional refrigerator illustrated in FIG. 1 is a refrigerator disclosed in Japanese Patent Laid-open Publication No. 9-28363. As shown in the drawing, a foodstuffs storage container 2 is provided at a top-mount type refrigerator in which a freezing chamber is positioned at an upper portion and a cooling chamber is positioned at a lower portion.
Many factors, such as temperature, humidity, environmental gas, microbe, light and etc., do influence on the freshness of vegetables. Because vegetables perform breathing and transpiration continuously, it is necessary to restrain the breathing and the transpiration in order to maintain the freshness of vegetables. Most vegetables, except for some kinds of vegetables that have trouble at low temperature, restrain the breathing at low temperature and the transpiration at high humidity.
For this reason, a general home refrigerator is provided with a foodstuffs storage container for exclusively storing vegetables as an independent space from the cooling chamber, so as to store vegetables in a fresh state for a long period. The foodstuffs storage container is kept at adequately low temperature and as high humidity as possible by moisture transpired from vegetables. Accordingly, the vegetables can be stored in the foodstuffs storage container in a fresh state for a long time.
Meanwhile, research of a method of maintaining the freshness of vegetables by using the light (another influential factor concerning the freshness of vegetables) is being pursued.
Relatively strong light has a bad influence of promoting color change and transpiration of vegetables, and relatively weak light has an effect of improving the maintenance of the freshness of vegetables. Also, weak light restrains chlorophyll degradation of green leaf and stem vegetables, and has an effect of keeping in vitamin C.
A refrigerator 1 illustrated in FIG. 1 is provided with an irradiation device 6 which irradiates weak light into the foodstuffs storage container 2, so as to prevent decrease of chlorophyll concentration of green leafy and stem vegetables, and resultantly prevent deterioration of the quality of leafy and stem vegetables. An illuminating lamp 8 is provided over the drawer-type foodstuffs storage container 2. When the drawer-type foodstuffs storage container 2 is opened, the illuminating lamp 8 emits light to allow a user to easily see the foodstuffs in a storage chamber 4. When the drawer-type foodstuffs storage container 2 is closed, the irradiation device 6 irradiates weak light to prevent deterioration of the quality if green leafy and stem vegetables.
Japanese Patent Laid-open Publication No. 11-159953 discloses a refrigerator provided with the irradiation device which is embodied by a light emitting diode (LED) which emits light within a visible light region. Accordingly, heat generation from the irradiation device is minimized, rise of temperature in the storage chamber is prevented, and irradiating efficiency is increased as compared to other irradiation devices.
Also, Japanese Patent Laid-open Publication No. 2005-49093 discloses a refrigerator provided with a red LED which emits light of a wavelength of about 660 nm to green leafy and stem vegetables.
And, Japanese Patent Laid-open Publication No. 2005-65622 discloses a refrigerator provided with a foodstuffs storage container which is partitioned into several storage chambers and irradiation devices which irradiate light of adequate wavelengths for kinds C vegetables stored in the storage chambers. More particularly, three color (red, blue and green) LEDs are used as a light source, and emitting colors of the light from the three color LEDs can be selectively combined according to the kinds of vegetables.
However, the above conventional refrigerator having the foodstuffs storage container has problems as follows.
The emitting colors of the light from the three color (red, blue, green) LEDs can be selectively combined, but it is not accurate that which of the red LED, the blue LED and the green LED respectively are effective to which foodstuffs. Therefore, such an irradiation device is not effective to the maintenance of the freshness of the stored foodstuffs and the prevention of the chlorophyll degradation.
Although the foodstuffs storage container is partitioned into several storage chambers, because a reference, by which the user classifies the foodstuffs and separately puts the classified foodstuffs into the storage chambers, is not clear, there is no effectiveness in partitioning the foodstuffs storage container into several storage chambers.
Also, means for selecting the emitting colors of the light from the three color LEDs is provided at the conventional irradiation device, but the selecting means is not practical due to lack of accurate information that which emitting color is most adequate for which foodstuffs. Although it is found that which emitting color is most effective to which foodstuffs by experiments, it is very difficult for the user to remember this information one by one to select the emitting color, or it is very troublesome for the user to search this information before selecting the emitting color.
Further, regarding the foodstuffs, the relationship of which with the emitting color is not experimentally found, the user cannot determine which emitting color is adequate or the foodstuffs and cannot be confident whether the user-selected emitting color is adequate for the foodstuffs or not. Thus, the user comes to distrust the irradiation device.
In order to keep the foodstuffs in a more fresh state for a long period, the humidity in the cooling chamber is set as high as possible. However, the higher the humidity is, the more various germs propagate in the cooling chamber. Also, the air of the cooling chamber is impregnated with a bad smell.